A question about Lucky Number Slevin (open spoilers for this 2006 movie)

We saw this movie for the first time last night on Netflix (Canada). Loved it.

I hope it’s all right if I spoil the movie at this point.

(Contemporaneous thread on the movie in question.)

One thing I’m wondering about:

Our main boy Slevin observed that Lindsey, the neighbour, was starting to play Columbo about Nick’s disappearance. At the same time, he seemed to be developing feelings for her.

So why didn’t he try to keep her from coming into contact with CoolKat? Why did he choose to reveal to her the situation he was in with the crime bosses (in the same way the audience was seeing it), thereby getting her involved even deeper?

Wouldn’t it have been safer for her (and possibly for him) to just hide the developments from her as much as possible? Maybe even disappear from Nick’s apartment for a few days while the main adventure unfolded, and reappear in her life afterwards?

I know the movie itself wouldn’t have been as interesting if he had acted differently. But with all the detailed planning involved in the grand scheme, it seems he was oddly careless in the first half of the movie about the danger she was in.

Obviously the answer is that it was required for the plot, but how about this explanation: He’s decided that the person he’s pretending to be would have told her, so he tells her rather than risk creating an incongruous thread that his targets could possibly pick up.